The invention relates to a rotary press, in particular a rotary pelleting press, with a rotor that can usually be rotated around a vertical axis, whereby the rotor comprises one upper and one lower punch guide and a die plate between the upper and lower punch guides, furthermore with upper and lower press punches which interact with the die holes in the die plate, whereby the rotary press comprises several stations, namely at least one filling station in which the material to be pressed is filled into the die holes, at least one dosing station, in which the material filled into the die holes is dosed, at least one pressing station, in which the material that has been dosed and filled into the die holes is pressed through the upper and lower press punches into pellets, and at least one ejector station in which the pressed pellets are ejected.
The invention also relates to a method for operating a rotary press, in particular a rotary pelleting press, with a rotor that can usually be rotated around a vertical axis, whereby the rotor comprises one upper and one lower punch guide and a die plate between the upper and lower punch guides, furthermore with upper and lower press punches which interact with the die holes in the die plate, whereby the rotary press comprises several stations, namely at least one filling station in which the material to be pressed is filled into the die holes, at least one dosing station, in which the material filled into the die holes is dosed, at least one pressing station, in which the material that has been dosed and filled into the die holes is pressed through the upper and lower press punches into pellets, and at least one ejector station in which the pressed pellets are ejected
This kind of rotary press is often used in different operating modes. For example, single-layer tablets can be produced with this kind of rotary press in a first operating mode and two-layer tablets in a second operating mode. Rotary presses exist that are designed in such a way that all process-relevant stations can remain in the rotary press during conversion and hereby assume new process functions. In other rotary presses, those process stations that are no longer needed and new process stations that are now needed are removed and/or fitted during a change in the operating mode. Rotary presses are known, for example, from DE 10 2007 061 081 B4 or DE 10 2007 057 791 B4. In the latter, the individual stations of the press are designed in such a way that they can be easily exchanged with each other.
Furthermore, it is sometimes necessary to dismantle or fit the rotor out of and into the rotary press in the course of the operation of rotary presses for maintenance or replacement purposes. One or more stations of the rotary press usually have to be dismantled and moved for this purpose. This applies in particular if the angular distance between two adjacent pressing stations has been designed such that the rotor cannot be passed between the pressing stations. This is the case, for example, when three pressing stations are distributed around the periphery of the rotor and these have an angular distance between each other of more than 90°, for example. WO 2009/112886 A1 describes a device and a method to exchange a die plate. Levering devices are provided with which at least one upper punch guide can be raised from the die plate. A pivot arm is also provided with which the die plate can then be swung out of the press.
The installation and removal of individual stations that is necessary to convert a rotary press between different modes of operation requires a lot of time in the known rotary presses. Furthermore, this work is usually carried out by hand, whereby trained specialists and to some extent special tools are required. There is also a risk of operating errors in the course of the manual conversion that could have a negative effect on the production process. The rotary press and/or the stations may also be damaged during the installation and removal of stations. This applies in particular during the very complicated removal of the rotor in such a rotary press. The flexibility when using such rotary presses is also restricted.